Exhaust systems are widely known and used with combustion engines. Typically, an exhaust system includes exhaust tubes or pipes that convey hot exhaust gases from the engine to other exhaust system components, such as mufflers, converters, resonators, etc. As known, a catalytic converter converts toxic by-products of the exhaust gases to less toxic substances by way of catalysed chemical reactions. The catalytic converter includes a substrate positioned within a housing that has an exhaust gas inlet and an exhaust gas outlet. As the exhaust gas flows through the substrate, pollutants such as carbon monoxide, unburned hydrocarbon, and oxides of nitrogen are converted to less toxic substances such as carbon dioxide and water, for example.
In one known configuration, a perforated plate is positioned upstream of the catalytic converter such the plate is parallel to an end face of the substrate. The plate is used to improve a uniform flow distribution and to increase emission conversion efficiency. While these plates have proved effective, there is always a need to further increase emission conversion efficiency.